Ratchet wrenches having motion transmission mechanisms are used in automotive, industrial, farm shop and home applications to install and remove threaded fasteners. The motion transmission mechanisms used in ratchet wrenches have structures that are operable to transmit torque applied to the handles of the wrenches to driven bodies or spindles coupled to threaded fasteners and alternatively prevent the transfer of torque to the driven bodies or spindles. Ratchet wrench motion transmission mechanisms with a driving gear and a spring loaded pawl are used to rotate a fastener in one direction and prevent rotation of the fastener in a reverse direction without removing the wrench from the fastener. A large amount of angular movement of the handle of these ratchet wrenches are required to rotate a fastener. The required angular movement of the handle of the ratchet wrench eliminates the use of the ratchet wrench in confined environments. Ratchet wrenches having motion transmission mechanisms that operate with a minimum of back lash or lost motion during the reverse movement have cylindrical rollers that engage ramps on driven bodies and cylindrical walls of drive members. Springs and elastic members are interposed between the rollers and driven bodies to hold the rollers in wedging position between the ramps and cylindrical walls of the drive members, such as the heads of wrenches.
Ratchet wrenches having cylindrical rollers biased with springs into engagement with inclined ramps on driven bodies and cylindrical walls of the heads of the wrenches are shown and described in the following U.S. patents and U.S. published patent application.
C. B. Lowry and R. Bernhard in U.S. Pat. No. 835,448 discloses a wrench with a handle joined to a head having an internal cylindrical wall. A body with a plurality of steel inserts providing ramps for rollers retained in carriages. Each carriage retains two rollers in engagement with two ramps and adjacent cylindrical wall of the head. Coil springs engage the body and carriages to bias the carriages to hold the rollers in wedging engagement with the ramps and adjacent cylindrical wall of head whereby clockwise movement of the handle and head rotates the body and counterclockwise movement of the handle and head does not rotate the body. The carriage is not anchored to the body.
S. O. Lawrence in U.S. Pat. No. 1,511,226 discloses a wrench having a handle joined to a head. The head has a cylindrical inside surface surrounding an opening for accommodating a body. The outer portion of the body has a series of pockets accommodating cylindrical rollers that wedge between the body and head for rotation in one direction and to release the rollers to prevent the body from rotation in a reverse direction. In order to avoid lost motion of the rollers, flat springs engage the rollers to hold the rollers in wedging positions in the pockets.
R. A. Johnson in U.S. Pat. No. 2,529,947 discloses a roller clutch wrench having a head at the outer end of a handle. The head has an internal cylindrical surface surrounding an opening. A clutch body located in the opening has spaced notches with ramps. Ridges located between the ramps contact the cylindrical surface of the head. A roller located in each pocket is biased with a spring into wedging contact with the ramp and cylindrical surface of the head whereby clockwise movement of the handle and head rotates the clutch body and counterclockwise movement of the handle and head does not rotate the clutch body.
C. T. Chang in U.S. Pat. No. 6,253,646 discloses a wrench having a handle joined to a head. The head has an inside circumferential wall having a plurality of arcuate recesses. A body with a cylindrical outer wall is located in an opening surrounded by wall with the recesses. Rollers located in the recesses engage the outer wall of the body to transmit torque from the head to the body during angular movement of the head and handle. A ring located on the body has C-shaped portions accommodating the rollers. A control device mounted on the head is used to rotate the ring to concurrently shift the ring to selectively move the rollers to clockwise and counterclockwise positions. A modification of the wrench has a head with a continuous inside cylindrical wall. The body has a plurality of ramps providing pockets for rollers. The ring biases the rollers into engagement with the inside cylindrical wall of the body whereby on angular movement of the handle in a clockwise direction the roller wedges between the ramps and inside cylindrical wall to rotate the body and on movement of the handle in a counterclockwise direction the rollers move to non-wedging locations in the pockets. The wrench is an improvement of a ratchet wrench having anti-reverse rollers and elastic members that bias the rollers into contact with ramps and a cylindrical wall of the head of the wrench.
M. Wang in U.S. Patent Application Publication No. 2018/0079055 discloses wrenches having unidirectional motion transmission mechanisms for rotating a nut or bolt head. Each wrench has a handle joined to a head having an internal cylindrical wall surrounding an opening. A body having inclined ramps is interposed in the opening and retained in the head. A cylindrical roller engages each ramp and adjacent cylindrical wall of the head. A spring between the body and roller biases the roller into contact with the ramp and adjacent cylindrical wall of the head. Movement of the handle and head in a clockwise direction wedges the roller into torque transmitting relationship with the ramp and cylindrical wall of the head thereby rotating the body. Movement of the handle and head in the opposite direction releases the torque transmitting relationship of the roller with respect to the ramp and cylindrical wall of the head whereby the body does not reverse rotate when the handle and head are moved in the reverse direction. One embodiment of the wrench has a holder having slots for accommodating the rollers. Elastic members or springs bias the rollers into contact with ramps and cylindrical wall of the head.